A typical table saw includes a cutting instrument, usually a saw blade, attached to a motor mounted beneath a work surface, commonly called a table. The table has an opening that allows a portion of the blade to extend through the table. To make a cut, a user places material on the table and directs the material through the rotating blade. To assist users in making accurate cuts, many table saws are adapted to receive fences or material guides.
One type of fence commonly found on table saws is the rip fence. The rip fence, also known as a guide assembly, is a table saw guide that assists users in making lengthwise cuts through material, as when cutting wood along the grain. Most rip fences traverse the table parallel to the cutting direction of the blade. In order to make cuts of varying width, a user slides the fence along the table closer to or farther away from the blade. To ensure an accurate cut is made, the fence should be securely fastened to the table.
In some instances when cutting a workpiece, which includes materials such as solid wood or wood composites, an event known as “kickback” can occur. When kickback occurs, the workpiece can be unexpectedly thrown toward the front of the saw and toward the user. Kickback not only damages the workpiece in these situations, but can present work conditions which are to be avoided.
Kickback can occur when ripping a workpiece if the wood pinches the blade because of internal stresses which are inherent in the workpiece. In other situations, if the workpiece rises up from the table of the saw while cutting, kickback can also occur. In addition, kickback can occur if the workpiece is pinched between the blade and the rip fence. This condition most often occurs due to a misalignment of the rip fence with respect to the plane of the saw blade. In view of the foregoing, it would be advantageous to provide a system to monitor, detect and mitigate kickback in a table saw.